Are your employees scared to take time off?

Your employees might be feeling pressured and overworked. Avoid low productivity in your workplace with these tips on vacation impact.

They might be getting paid time off, but close to half of American workers aren’t taking it—or aren’t taking as much of it as they’re entitled to. And that’s making for a workforce that’s not only overworked and under stress, but actually being pressured to forego time that they’re entitled to.

So says “The PTO Pressure Report” from Kimble Applications, which finds that not only have 47 percent of employees not taken as much PTO as they’re entitled to, 21 percent admit to having left more than five vacation days unused. According to survey respondents, workload-related stress is the top reason so many are failing to use all the PTO they’re entitled to: 27 percent say they just have too many projects or deadlines to take time off, and 13 percent dread the heaps they’ll find on their desks when they get back.

Their bosses aren’t helping, either, with 19 percent of respondents saying that they’ve felt pressured by employers or managers to abstain from vacation. Not only that, more than a quarter are actually nervous or even anxious at the thought of submitting a time-off request; 19 percent worry about being away from work, while 7 percent fear that their requests will be denied.

But businesses could actually be shooting themselves in the foot by keeping such a tight rein on employees. Says the report, “These managers likely don’t realize that this is having a direct, negative impact on the business, as past research indicates that employees who take most or all of their vacation time each year perform better and are more productive than those who do not.”

Even if they get to go on vacation, it’s not doing a lot of them much good. They’re too wired into the job, with 48 percent saying they proactively check in on vacation. A surprising 19 percent do so every day, with another 29 percent doing so periodically. And the boss isn’t making it easy to be on vacation once they get to go; 29 percent of workers say they’re expected to be available for emergencies, and another nine percent say they’re expected to check in frequently. Can’t exactly unwind too well with that hanging over their heads, which means they get back to work stressed out from making sure they satisfy vacation’s employment obligations.

They think they’ll get ahead that way, though—at least 14 percent believe that if they leave that vacation time on the table, they’re more likely to succeed and move up in the ranks. And 19 percent say that’s more important to them than the vacation time they’re abandoning—they’d give up their vacation time for a whole year if it meant they’d nail a promotion.

Younger employees are more willing to work instead of take time off than their elders ; 25 percent of those aged 25–34 feel this way compared to only 17 percent of those aged 55–64.

What businesses may not realize is how important PTO is for the company’s bottom line. Mark Robinson, co-founder of Kimble Applications disagrees. “I am an advocate of giving people a reasonable vacation entitlement and then encouraging them to take it,” he says in the report. ”My experience is that businesses work best if there is clarity about this and people feel confident about planning their vacation well in advance. That is better for the individuals and it allows the business to forecast and budget better too.”

Robinson adds, “American businesses sometimes offer unlimited time off—but they know that in most cases that ends up with people taking less time off. Also, in businesses where people don’t feel confident enough about taking vacations to plan them well in advance, there can be an issue at the end of the year when they suddenly all disappear at once. Successful, sustainable organizations learn to plan their business around PTO time.”